Google: How the 'needle-free' blood-drawing watch would work

Speculation that Google's next piece of wearable technology will be a blood-drawing smartwatch that helps diabetics monitor blood-sugar levels is growing, after the tech giant filed a patent application for the device. The gadget described in the patent works by pricking the finger and drawing blood without using a needle.

A detachable chamber is placed on top of a fingertip and a gas-powered microparticle is blasted through it towards the skin, according to Google's application filed with the US Patent and Trademark Office. The microparticle – which could be as small as 10 microns, or 10 millionths of a metre – pierces the skin and the device draws a small vial of blood into a pressurised chamber.

Now containing a blood sample, the device is reattached to the watch, which could be used to measure glucose levels. Google declined to confirm if the invention would be used to create a new product.

"We hold patents on a variety of ideas – some of those ideas later mature into real products or services, some don't," a Google spokesperson told The Verge. "Prospective product announcements should not necessarily be inferred from our patents."

Diabetics must monitor blood sugar levels several times a day to avoid complications from the disease, often by drawing blood samples with a needle from a fingertip.